C4 GP -07 No connection to ECU / TCU & error U1313

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GrandPicasso07
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Joined: 03 Jun 2024, 20:33

C4 GP -07 No connection to ECU / TCU & error U1313

Post by GrandPicasso07 »

My -07 Grand Picasso (petrol) gives "faulty" messages from ABS, ESP, Handbrake, Gearbox etc., seems to be quite common problem.
Tried to get error codes with simple OBD reader & Android App, gives just U1313 (stays after erase) and U0404 (can be reseted, for a short time). I drove to local car parts store that has generic bigger, automated OBD / diagnostic reader. It could not connect to ECU / ABS unit. Have not yet found any local guys with Lexia. (I'm a fresh Citroen owner so I don't have my own Lexia, yet.)

I guess the problem might be the wiring somewhere? I have checked now;
- fuses & connections above battery (battery was replaced two years ago, should be ok)
- fuses in fuse box next to battery
- first glimpse with the cable punch near battery & fuse box, no corroded/broken cables sighted yet

Before checking brake light switch and cables around every tire, is it possible that those locations could prevent the connection to control units?
I could check connections to ABS unit connector, if I could find which pins are related with 12V and ground.
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xantia_v6
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Re: C4 GP -07 No connection to ECU / TCU & error U1313

Post by xantia_v6 »

Maybe you have seen viewtopic.php?t=68753 It is not definitive, but somewhere to start.
GrandPicasso07
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Joined: 03 Jun 2024, 20:33

Re: C4 GP -07 No connection to ECU / TCU & error U1313

Post by GrandPicasso07 »

Not sure if ZeroSix got his/her problem solved on that thread. The linked video I saw earlier.

I wonder, can faulty ABS sensor create this kind of problem? Or would diagnostic tools just pinpoint "faulty ABS sensor rear left " etc.?
GrandPicasso07
Posts: 4
Joined: 03 Jun 2024, 20:33

Re: C4 GP -07 No connection to ECU / TCU & error U1313

Post by GrandPicasso07 »

What's Your opinion, is the red-white wiring OK? Could it be just dirt or color from the cars body?

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GrandPicasso07
Posts: 4
Joined: 03 Jun 2024, 20:33

Re: C4 GP -07 No connection to ECU / TCU & error U1313

Post by GrandPicasso07 »

Tested also the brake light switch, seems to be working (one pair of pins gives signal to multimeter and the other pair gives when pushing the sensor).